Heater for oil recovery



Sept. 26, 1967 J. H. PHELAN nl HEATER FOR OIL RECOVERY 2 Sheets-Sheet l Filed Feb. 17, 1965 Fig./

John Henry Phe/an Fig. 4

INVENTOR,

J. H. PHELAN ll'l HEATER FOR on. RECOVERY Sept. 26, 1967 2 sheets-sheet 2 Filed Feb. 17, 1965 Paten-'ted Sept. 26, 1967 3,343,665 HEATER FR GIL RECVERY John Henry Phelan III, RO. Box 2270, Beaumont, Tex. 77 7 04 Filed Feb. 17, 1965, Ser. No. 433,335 4 Claims. (Cl. 166-61) This invention comprises a novel and useful heater and method for oil recovery and more particularly pertains to a thermal recovery method and apparatus for use with oil wells. More specifically, the present invention contemplates the provision of an improved heat exchanger adapted to be positioned within an oil well, sulfur well or the like to facilitate the thermal recovery of such deposits.

When the viscosity and temperature of the oil recovered from an oil producing formation is suciently low, the rate of flow of the oil is detrimentally eected .and often to such an extent that further production of oil from the well becomes impractical or impossible. Further, oil being produced by the flow tubing of the well tends to deposit parain in the piping which further obstructs and sometimes completely halts further production- When this condition arises, it is often necessary to abandon the well or at best to engage in laborious heat treating operations calculated to increase the viscosity of the oil so as to thereby facilitate its flow and thus stimulate production from the well.

Heretofore such heat treating method required for the thermal recovery of oil have been relatively expensive, laborious and more or less complicated in their operation and often are attended by an undesired contact of the heating fluid with the oil itself.

It is therefore the primary purpose of this invention to provide a method and apparatus for the thermal recovery of oil which will largely overcome the heretofore encountered difficulties of previous thermal recovery methods.

It is a further object of the invention to provide a method and an apparatus which may be easily and effectively applied to well installations for the purpose of heating the oil in the formation which is contiguous to the well bore as well as the oil in the flow tubing and the well bore for the purpose of raising its temperature, increasing its viscosity and rendering the oil more readily flowable into the well bore and through the tubing.

A further object of the invention is to provide an apparatus and a method which may be readily installed in a well bore and will enable a relatively greatly :increased rate of heat flow from the apparatus into the contiguous region of an oil productive formation thereby enabling a more efficient use of the heating means for stimulating flow of oil from'the formation to the well bore.

Still another object of the invention is to provide an apparatus and method which will enable the oil flow from a plurality of productive formations to be individually stimulated and promoted through the application of a relatively localized heating means disposed in a good heat exchange relation therewith.

A further object of the invention is to provide a thermal recovery system including an apparatus and a method which will enable a heating fluid to be continuously circulated from a suitable heating source at the surface into and through a well bore in a closed circulatory path of travel which is sealed from the oil within the well bore to thereby effectively heat the oil in the well bore and in the contiguous oil producing formations penetrated by the well bore.

Yet another object of the invention is to provide a thermal recovery system in accordance with the immediately preceding object which may selectively utilize all or a portion of the oil produced from the flow tubing of the well bore as the heating fiuid by introducing it into the heating system, heating the introduced oil, circulating the introduced oil through the heating system and then discharging the heated oil after circulation through the system to a suitable destination whereby not only is the produced oil from the flow tubing used as a heating medium for the formal recovery of `further oil but also is in itself heat treated to better condition it for subsequent use.

These together with other objects and advantages which will become subsequently apparent reside in the details of construction and operation as more fully hereinafter described and claimed, reference being had to the accompanying drawings forming a part hereof, wherein like numerals refer to like parts throughout, and in which:

FIGURE 1 is a somewhat diagrammatic view showing the thermal recovery system of this invention operatively associated with a conventional oil well;

FIGURE 2 is an enlarged detail view in vertical central section through the upper portion of the well casing showing the manner in which the heating system of this invention is associated therewith;

FIGURE 3 is a detailed view in vertical central section through the lower portion of the Well casing and showing further details of the heating system installed therein;

FIGURE 4 is a horizontal sectional view taken upon an enlarged scale substantially upon the plane indicated by section line 4 4 of FIGURE 2;

FIGURE 5 is a further horizontal sectional view taken upon an enlarged scale substantially upon the plane indicated by section line 5-5 of FIGURE 3; and

FIGURE 6 is a further detail view taken upon a reduced scale substantially upon the plane indicated by section line 6 6 of FIGURE 3.

In the accompanying drawings, reference is made first to the diagrammatic view of FIGURE l wherein the numeral 10 designates the well bore extending into an oil productive formation and penetrating and communicating with one or more oil producing formations therein. The well may be of any conventional type such as a cased well, the casing being indicated at d2 and having the usual well casing head 14 through which extends a flow tubing 16 of conventional type by means of which oil is produced from the well. It is immaterial for the purpose of this invention whether the oil is produced by formation pressure or by artificial flow producing means.

Referring to FIGURE 3 it will be observed that the casing 12 contiguous an oil producing formation is perforated as at 20 to enable the flow of oil from the formation into the well bore in the usual manner. Further, the inlet end of the flow tubing 16 may be surrounded with a conventional screen 22. to reduce the inlet of sand from the formation into the flow tubing.

Although but one perforated casing section and oil producing formation has been illustrated in the drawings, as shown in FIGURE 3, it will be appreciated that the well bore and casing may extend through a plurality of such formations or stratas for producing oil therefrom.

When it is desired to facilitate the thermal recovery of oil and/or to prevent parat-lining of the flow tubing and the like, the heating system of this invention is installed in the well bore. This installation may be effected in an originally completed well bore or in one in which the recovery of oil has diminished or been halted because of the viscosity or low temperature of the oil.

The apparatus for effecting a thermal recovery of oil in accordance with this invention consists of a conduit system which extends from the surface into and through the well bore and forms a closed circulating system for the passage of a heating fluid or heating medium through the well bore. Thus, it includes an inlet pipe 30 and a corresponding outlet pipe 32 which extends from above the surface of the ground preferably through the casing head 14, down through the well bore to the bottom thereof or to any desired producing formation penetrated by the well bore, together with a heat exchanger, boiler' or a fluid heater 34 preferably disposed upon the surface and supplied with heat from any suitable source, not shown. -As shown in FIGURE l, the inlet pipe 3G of the conduit system is connected to the output side of the uid heater 34 and receives the heated fluid medium therefrom. The output or outletfpipe 32 of the conduit system is similarly connected to the input side of the uid heater 34. In its simplest form, there is thus provided a closed circulatory path of travel for a heating uid from the boiler into and out of the well bore.

It is to be understood that circulation may be forcibly effected by any suitable means, not shown, which forms no part of the present invention. The inlet and outlet pipes within the well bore are preferably disposed in a good heat exchange relation with the oil in the Well bore in the flow tubing for the purpose of preheating the latter. However, and more important, the conduit system is disposed in highly effective heat exchange relation with each of the productive formations through which the well bore passes and which it is desired to apply the thermal recovery process of this invention thereto.

Referring now particularly to FIGURES 5 and 6 it will be observed that adjacent each of the perforated well casing sections which are contiguous each to an oil production strata or formation, the conduit system is provided with a portion to obtain a greatly increased heat radiating action. Thus, each of these portions of the conduit systems includes a plurality of preferably vertically extending branch conduit sections 36 which are joined at their top and bottom portions by .circumferentially extending conduit sections 38 to effect an increased surface area for radiation. The conduit sections 36 are disposed in circumferentially spaced relation about substantially the entire periphery of circumference of the well bore casing 12 closely adjacent the latter so that they will be positioned for most effective heat transmission and radiation through the perforations 20 to the formation horizon for the purpose of heating the latter, lowering the viscosity of the oil and thereby stimulating and promoting flow of oil from the formation into the well bore.

In some instances, the inlet and outlet pipes 30 and 32 may be so disposed that there is substantially little heat radiating effect therefrom into the oil of the well bore other than at the regions of increased heat radiation for the purpose of thermally treating a productive formation as abovementioned. In other instances, however, it will generally be found preferable to allow a relatively less heat flow from the inlet and outlet pipe 30 and 32 into the oil of the well bore in order to maintain the temperature thereof suiiicient to effect ready flow of oil into and through the tubing without danger of the forming of paraflin deposits therein.

In a more complex and preferred form of the invention however, in addition to the thermal recovery of oil as above mentioned, the installation provides a means for very beneficially treating the oil produced by the well bore and preconditioning it for more eicient and better subsequent handling. For this purpose, the apparatus and the method of this system contemplates and provides for the introduction of at least a portion of the oil produced by the flow tubing into the heating circulating system as the heating uid thereof. This results in subjecting the produced oil to a heating effect which beneficially treats the oil in preparation for subsequent use.

For this purpose, as shown in FIGURE 1, there is diagrammatically indicated an oil storage tank 40 into which oil produced by the flow tubing 16 is normally delivered as by a delivery conduit 42, under the control of a multiple passage valve 44.

The control valve 44 is connected by a conduit 46 with a further multiple way control valve 48 which is disposed in the return pipe 3'2. From the control valve 48 there also extends a delivery conduit 50 which likewise communicates with the storage tank 40.

It will be understood that the storage tank merely diagrammatically indicates any desired destination for the oil produced from the well bore.

The arrangement of this form of apparatus enables the following operations to be performed.

When it is desired to deliver the entire output of the ow tubing to the storage tank 40, the heating system is then rendered self-contained, closed and sealed from the produced oil. For this purpose, the valve 44 is so adjusted that the flow tubing delivers solely to the conduit 42 and thus to the storage tank 40, with the branch conduit 46 being cutaoff from the flow tubing. At the same time, the control valve 48 is so adjusted that the branch conduit 5t) and its connection to the storage tank 40 is likewise disconnected from the return or outlet pipe 32. Consequently, with the conduit system filled with a heating lluid of any `desired character, whether water or oil, the fluid heated by the boiler '34 is delivered through the inlet pipe 30 into the conduit system in the well bore, passing through the various heat exchange portions thereof, and is then returned to the return or outlet pipe 32 back to the boiler. Thus, Ia closed forced circulating system of the heating 4fiuid is elected with the heating fluid being separated from all direct contact with the oil -within the well bore and serving as a means to apply heat as desired.

However, the system also admits of a modified operation in Awhich all or any desired portion of the oil produced by the ow tubing is utilized as all or a part of the heating uid in the circulating heating system and also is beneficially heat treated in preparation to its delivery to the oil storage means 40. For this purpose, the valve 44 is adjusted so that the conduit 42 is disconnected from the ow tubing 16. The valve 48 in turn is adjusted so that the conduit 46 is placed in communication with the outlet pipe 32 and its connection to the boiler 34. Further, the multiple way valve 4S now places the outlet pipe 32 where it emerges from the well bore into communication with the branch conduit 50 which in turn is in communication with the storage means 40. Depending upon the extent of opening of the control valve 44, all or any desired portion of the oil produced by the ow tubing 16 is now delivered to the boiler where it is heated, is then circulated through the fluid conduit system within the lwell bore to perform its heating operation, and upon emerging from the well bore through the outlet or return pipe 32 is discharged through the conduit section S0 into the storage means `40. In this manner, all or any portion of the produced oil is heat treated by its passage through the boiler facilitating .and preconditioning the oil to facilitate further treatment thereof as may be required in accordance Iwith conventional practice.

The system lends itself to ready adaptability for different sizes and types of well bores and may be easily installed in or removed from a well bore when only temporary need of its function is required. Further, it provides an effective means for the recovery of oil deposits which have too low a viscosity and temperature 'to otherwise permit a practical recovery.

The foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifcations and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly all suitable modifications and equivalents may be resorted to, falling within the scope of the invention as claimed.

What is claimed as newis as follows:

'1. An apparatus for the thermal recovery of oil from an oil bearing formation traversed by a well bore having an oil producing flow tubing therein comprising means vincluding a conduit system disposed in a Well bore and constituting a closed circulatory path of travel for a heating fluid, said conduit system being in good heat exchange relation with the oil in said flow tubing and well bore whereby to heat and lower the viscosity thereof, means for heating and circulating a heating fluid through said conduit system, means in said conduit system disposed contiguous said formation for effecting a relatively increased rate of heat ow from said fluid into said formation thereby increasing ow of oil from the formation into said Well bore, said means in said conduit system disposed contiguous said formation comprising a plurality of vertically extending branch conduit sections, said vertically extending conduit sections being joined at their top and bottom portions by circumferentially extending conduit sections whereby said heating fluid follows a sinuous path in its circulatory path through said vertically extending branch conduit sections, said circumferentially extending conduit sections being disposed so as to position said vertically extending conduit sections in encompassing relation to said oil producing flow tubing adjacent the oil bearing formation.

2. The combination of claim 1 including means for introducing oil into said conduit system as said heating References Cited UNITED STATES PATENTS 1,876,401 9/ 1932 Chateld 165-143 1,918,601 7/1933 Jacocks 165-143 2,349,536 5/1944 Bancroft 166-61 2,907,644 10/ 1959 Cunningham 16S- 145 X 2,911,047 ll/ 1959 Henderson 166-40 X 2,914,124 ll/ 1959 Ripley 166-40 X CHARLES E. OCONNELL, Primary Examiner.

NILES C. BYERS, IR., Examiner. 

1. AN APPARATUS FOR THE THERMAL RECOVERY OF OIL FROM AN OIL BEARING FORMATION TRAVERSED BY A WELL BORE HAVING AN OIL PRODUCING FLOW TUBING THEREIN COMPRISING MEANS INCLUDING A CONDUIT SYSTEM DISPOSED IN A WELL BORE AND CONSTITUTING A CLOSED CIRCULATORY PATH OF TRAVEL FOR A HEATING FLUID, SAID CONDUIT SYSTEM BEING IN GOOD HEAT EXCHANGE RELATION WITH THE OIL IN SAID FLOW TUBING AND WELL BORE WHEREBY TO HEAT AND LOWER THE VISCOSITY THEREOF, MEANS FOR HEATING AND CIRCULATING A HEATING FLUID THROUGH SAID CONDUIT SYSTEM, MEANS IN SAID CONDUIT SYSTEM DISPOSED CONTIGUOUS SAID FORMATION FOR EFFECTING A RELATIVELY INCREASED RATE OF HEAT FLOW FROM SAID FLUID INTO SAID FORMATION THEREBY INCREASING FLOW OF OIL FROM THE FORMATION INTO SAID WELL BORE, SAID MEANS IN SAID CONDUIT SYSTEM DISPOSED CONTIGUOUS WITH FORMATION COMPRISING A PLURALITY OF VERTICALLY EXTENDING BRANCH CONDUIT SECTIONS, SAID VERTICALLY EXTENDING CONDUIT SECTIONS BEING JOINED AT THEIR TOP AND BOTTOM PORTIONS BY CIRCUMFERENTIALLY EXTENDING CONDUIT SECTIONS WHEREBY SAID HEATING FLUID FOLLOWS A SINUOUS PATH IN ITS CIRCULATORY PATH THROUGH SAID VERTICALLY EXTENDING BRANCH CONDUIT SECTIONS, SAID CIRCUMFERENTIALLY EXTENDING CONDUIT SECTIONS BEING DISPOSED SO AS TO POSITION SAID VERTICALLY EXTENDING CONDUIT SECTIONS IN ENCOMPASSING RELATION TO SAID OIL PRODUCING FLOW TUBING ADJACENT THE OIL BEARING FORMATION. 